In recent years, light emitting diodes (LEDs) has been widely applied and play a more and more important roles in various fields like display system, lighting system and automobile tail light. The LED with (AlxGal 1-x)0.5 InP active area has high internal quantum efficiency. However, external quantum efficiency of traditional LED has been restricted by many factors like internal total reflection, metal electrode blocking and light absorption by GaAs semiconductor material. For those LEDs growing over light-absorption substrates, a good part of light is finally absorbed by the substrate. Therefore, for those traditional LED structures, external quantum efficiency remains low even internal photoelectric converting efficiency is high. Methods to improve LED light extraction efficiency include thinning window layer, surface roughening, transparent substrate, inverted pyramid structure, etc.